Rheostat and operating means therefor.



W. A. TURBAYNE.

RHEDSIAT AND OPERATING MEA-NS THEREFOR.

APPucArlon mw we. 19. 1914.

1,25 1,594. Patenteil Jan. 1, 1918.

i 'UNITED STATES PATENT OFFICE.

WILLIAM A. TURBAYNE, OF NIAGARA. FALLS, -N EW YORK ASSIGNOR TO U. S. LIGHT HEAT CORPORATION, VOF NIAGARA FALLS, NEW YORK., A CORPORATION OF NEW YORK.

i BHEOSTAT AND OPERATING MEANS THEREFOR.

To all whom it ma concern Be it known t at I, lVrLLLiM A. Ton- BAYNE, a citizen of the United States, resid ing at Nia ara Falls, in the county of Niagara an( State of New York, have invented' nevir `and 4useful lmprovements in Rhcostats and Operating Means Therefor, of which the followingV is aV full, clear, concise, and exact description', referencebeing had to "the accompanying drawing, forming a art of'this specification.

Il`his invention relates to improvements in rheostats and operating means therefor.

A rheostat is employed in many systems of automatic regulation in which it is desired that the rheostat shall remain inactive until certain predetermined circuit conditionsobtain, when it is automatically brought into action.' Such a system is extensively emloyed-in connection with ,electric car lightcars. `In zailivay lighting i ing-on railw systems, an 'ax e-driven generator furnishes current Vto light theV lamps and charge a storage battery; The battery supplies 'the lamps when t e generator. 4is-operating at low speedor is at rest.' The generator is regulated by means of variable resistances 1n the 'field circuit of 'the generator. It is def sirable to bring these resistances into operation ii nn certain definite circuit conditions obtaining in the system'. Thus, current-controlled resistances are brought into opera-- tion at definite current values to limit the output of the generator or the charging current for the battery. Also, voltage-con trolled resistances are brought into operation at definite voltages across the system to regulate the battery charge or other electrical conditions, Various conditions of service demand various arrangements, but' the underlying principle is common that at some definite current or voltage value the regn- `lator must be brought into operation.

An object of the present invention is to provide a variable resistance having operating means for bringing the resistance into operation under conditions which may he accurately.predetermined.

Another object is to provide a variable resistance having a single. operating coil for bringing the resistance into operation and thereafter controlling the variation thereof.

Another object is to provide a variable resistance and operating means which are not Specification of Letters Patent. VApplication led August 19, 1914. Serial No. 857478.

Patented J an. 1., 1918.

thrown out of adjustment by the rough `usage incident to cai-'lighting service.

Another object is to provide a compressible rlieostat having a single operating coil for bringing t-he rheostat. into operation at a predetermined current strength through the-coil and which will thereafter be op erated by the lcoil responsive to a different value of current through the coil, to vary the resistance. l'

The above 4and other objects may be attained by the embodiment of the invention illustrated in ,the accompanying drawings.

The views in' thedrawings are as follows:

Eigure 1 is a front elevation of the rheo- Stat.

Fig. 2is a. top plan thereof. Fig-3 is a vertical section on the line A of Fig. 1.

Fig. 4 is .a vertical B-BoiFig. 3. I

In. a o o-pending application, Serial No. 762,053, filed April 18, 1913, Patent No. 1,131,176, issued March 9, 1915, certain of the broad features of the invention are described andclaimed.

In the embodiment of the invention herein illustrated, the variable resistance is in the foi-in of a compressible rhcostat, although it is obvious 'that other forms of rheostat may section on the line be employed. The resistance elements of the rheostat comprise a plurality of contacting electrodes 10 of carbon or other suitable material, preferably in the form of disks.- The carbon disks are arranged hetween a relatively fixed abutment 11 and a movable abutment 12. -The electrical resistanee of the rheostat is varied bv varyin the pressure on the series o disks. lV ien the pressure is increased, the electrical resistancel decreases, 'and when the pressure is relaxed, the electrical resistance increases.

The operating means for varying the pressure includes an electromagnetic winding 13 on the parallellegs 14 of a horse-shoe inagnet. The magnet has an upper pivoted armature 15, adapted to be attracted t0 the upper poles of the magnet, and a lower pivoted armature 1G adapted to he attracted to the lower poles. A magnet frame 17 snpports the carbon disks 10 and the windings. A brat-liet 1S on the frame. provides a pivotal attachment for the armature 15, and a bracket 19 provides a pivotal attachment for nated the armature 16. The armature 15 is normallyl held in retracted posit-ion away from the 'magnet by a spring 20 attached to the arm 2 1, extendin from the armature 15, beyond its pivot.` he spring is adjustable by an adjusting'bolt 22 to which one Vend of the spring is attached. Adjustment of the bolt is secured by a nut 23 threaded on the bolt and bearin against the frame17. The armature 15 is pivotally attached to a rod 24 which carries the movable abutment 12 for the carbon disks. The amature 15 is provided with a. laminated portion 25 of good magnetic material, adjacent theupper pole faces of the magnet. The upper pole 'faces are cut away diagonally at 26 and the lami- V ortionof the' armature has its ends beveled) so as to provide a long range c.' action and also ,to give 'an increasm attraction as the amature moves downw'ar This increasing-attraction compensates for the" increasing counter-pressure on the carbon disks as they are oom ressed. Movement oil the armature away m the-ma et is-limned by'an adjusting screw 2'( carried in a bracket 28 supported on the magnet-frame;

'The llgweraixnatllllrtzlal 16 lsnormall tracted y vity, oug 't ma -I provided wil-liga' retracting spring,Y desired. Its movement away from the magnet is limited by an adjusting screw 29 'carried in bracket 30 supported from .the magnet frame. The armature carriesa bridging member 31 of material of low magnetic reluctance This member is adapted to bridge the lower pole pieces when the armature isattracted and( provide a path. of low magneticfr'eluctance for the flux of the .-meeg'for a'purpose hereinafter described. e'lower amature is designed to act as arelay to control external circuits or the circuit throlighthe rc-V sistauce elementsand tovthisend carries a resilient contact 32." This cntact is adapted to make contact with adjustable'upper and lower contacts 33 andV 34 which are provided with proper external leads.

A. common dash-pot studies the. action .of both armatures and-preventsthe jars and vibrations of service `from affecting therarmatures.l The Aupper amature is pivotall y connected to the cylinder 35 of the dash-pot and the lower armature is pivotally connectcd to the piston'36.

The rheostat operates as follows: The normal upper air gap-between the armature and pfrles is made so great that the amature is nuf. attracted by energization of the windings till se long as the lower air gap is open. B v

has causing thc uppcrarm'ature to 'remain ."mt-L'the reluctance of the magnetic circuit is maintained constant so that the lower armature may be, accurately adjusted by. means of the screw 29 to close at a definite encrgization of the coil. As soon as the lower armature is attracted the member 31 The device may be readily set to rcs ondA .to different current values. in the win '-by varying the normal positions of the armatures by means of the adjustable stops.

. It is possible to set the lower amature to respond to a definite voltave across the coil or indefinite current value tlxrough the same, which, asfalready explained, would be insuficient to operate the rhestat as long as the lo wer air gap is open. As soon as the lower amature is. raised and the lower. air gap eliminated2 theupper amature is within the radius of influence of the magnet and may -beset to o rateinresponse to-a definite ings value of vo tage across the coil'or current therethrough. Thus, in a unitarj'ndevice, it-

is poble tofemploy asingle 'normallyenergized coil which will prevent operation of the regulator until certain deiinite'- circuit conditions obtain, after which point the f regulator will automatically operate to maintam - condi ons may be different from those which initiallycaused the regulator to respond.

, The' improved arran ent of a single 'i dashpot controlling bo armatures prevents jars to which the regulator may subjected from prematurely closngthe air-gapfand causing operationof the regulator ore proper conditions have been reached.

It is tobe understood that the embodiments of the invention herein described are merely for the urposeof illustration, as it is apparent Y construction-'and am cnt of parts maybe made without'lsacrixiig-the advanta es plropercpnditions in the system, which' at many-modifications in details of sible rheostat and electro-magnetic means for' compressing said' rheostat, said electro-mag- -netic means being provided with means for increasing the eil'ectiveness thereof to compensate for increasing resistance to compression as said rheostat is operated, said electro-magnetic means including an operthe resistance of said r oisaid dash pot.

ating member normally ine'ectiveto vary the rheostat, and a member responsive to a predetermined energization-of the electromagnetic means for rendering-the operating member e'ective.

3. Regulating means includ' stat, a member for operating rheostat, a pair of ,windings arranged on parallel cores, an armatureadapted to bridgethe air gap between adjacent ends of said cores and an armature controlling said rheostat o rating member normally outside the ra ius of infiuence of said winding butautomatically brought into said influence by the decrease n reluctance, as said first is Aoperated to close the air gap.

4. Regulating' means for an electric circuit including a rhe'ostatilmeansfor'varying a rheomagnetic winding normally ineffective to operate said means and means operated `by said winding for increa'sin the radius of iniuence of said winding to ring said rheostat operating means within the lnfluenee of said winding.

5. In a regulator, an electro-magnetic winding, a pair of armatures, separately movable thereby, anda dash pot for steadying the operation of said armatures, one o f said armatures being connected to the piston ot an the other armature beto the cylinder of the dash ing connecte 6. A. compressible rheostat including a resistance element adapted to be compressed and an electro-magnetic windin for controllin the compression Vof sai element, said windin havlng an armature normally uninfiuence by current through said winding, said armature being mechanically connectd to the resistance element to compress the same, said winding also having a sec ond armature adapted to be attracted by said magnetlc circuit of sai winding and thereby to cause the first armature to be operated by said winding.

7. A compressible rheostat including a resistance element adapted to be compressed, an electro-magnetic winding for controlling the compression ofisaid element, said winding having an armature normally uninluenced by current through said winding, said armature. being mechanically connected to the resistance element to compress the same, said winding also having a second ar- .winding and to reduce the reluctance of the eostat, an electro.

'-'the'lirst armature to be operate mature adapted to be attracted by said winding to reduce the reluctance of the mag` netic circuit-of said winding andjthereb to cause the first armature to beo said winding, and a sin le dara steadying the operation'o both ofsaid ar.- matures. y

8. A compressible rh'eostat including a resistance element adapted t0 be compressed, an electro-magnetic winding for l'controlling thel compression of said element, said winding Vhaving an armature normally umnuenced by current through said winding, 'said armature being mechanically connected to the` resistance element tocompress the j by. pot v for same, said winding also having a second armature aldeafzted to be attracted by said winding to netic circuit of said winding and thereb to cause the first armature to b'e o ratedy by said winding, and a single das pot for steadying the o ration of both of said armatures, one o u-said armatures being me- -chanically connected to the movablepiston o f s'aid dastlixmt and the other armature being connec to thel movable cylinder within which said piston operates. 9. A compressible rheostat sistance element adapted'to be ompressed, an electromagnetic winding forfcpntrolling the compression of said element, said winding having an armature normally uninf fluenced by. current; through said winding said arm'ature being mechanically connected to the resistance element to compress the same, said windin 'also havlng a second aruce the reluctance ofthe mag-V including '.a' remature adapted to e'attracted b said winding 'to reduce the reluctance of t 'y e magnetic circuit of said winding and ther-eb;

nesses. WILLIAM A. TURBAYNE.

Witnesses: D. E.. QUILLINAN; Jas. L. Concl-n.111. 

